scholarly journals Are Single Polymer Network Hydrogels with Chemical and Physical Cross-Links a Promising Dynamic Vibration Absorber Material? A Simulation Model Inquiry

Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5127
Author(s):  
Leif Kari
Keyword(s):  
Simulation Model ◽  
Loss Factor ◽  
Polymer Network ◽  
Vibration Absorber ◽  
Vibration System ◽  
Frequency Range ◽  
Dynamic Vibration Absorber ◽  
High Loss ◽  
Dynamic Vibration ◽  
Cross Links

Tough, doubly cross-linked, single polymer network hydrogels with both chemical and physical cross-links display a high loss factor of the shear modulus over a broad frequency range. Physically, the high loss factor is resulting from the intensive adhesion–deadhesion activities of the physical cross-links. A high loss factor is frequently required by the optimization processes for optimal performance of a primary vibration system while adopting a dynamic vibration absorber, in particular while selecting a larger dynamic vibration absorber mass in order to avoid an excess displacement amplitude of the dynamic vibration absorber springs. The novel idea in this paper is to apply this tough polymer hydrogel as a dynamic vibration absorber spring material. To this end, a simulation model is developed while including a suitable constitutive viscoelastic material model for doubly cross-linked, single polymer network polyvinyl alcohol hydrogels with both chemical and physical cross-links. It is shown that the studied dynamic vibration absorber significantly reduces the vibrations of the primary vibration system while displaying a smooth frequency dependence over a broad frequency range, thus showing a distinguished potential for the tough hydrogels to serve as a trial material in the dynamic vibration absorbers in addition to their normal usage in tissue engineering.

scholarly journals Design of a hybrid proportional electromagnetic dynamic vibration absorber for control of idling engine vibration

2019 ◽  
Vol 234 (1) ◽  
pp. 56-70
Author(s):  
Tao Fu ◽  
Subhash Rakheja ◽  
Wen-Bin Shangguan
Keyword(s):  
Magnetic Force ◽  
Element Model ◽  
Geometric Parameters ◽  
Vibration Absorber ◽  
Electromagnetic Actuator ◽  
Primary System ◽  
Frequency Range ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
Engine Vibration

A hybrid proportional electromagnetic dynamic vibration absorber consisting of an electromagnetic actuator and an elastic element is proposed for control of engine vibration during idling. The design of the proportional electromagnetic actuator is realized considering the geometric parameters of the core to achieve nearly constant magnetic force over a broad range of its dynamic displacement but proportional to square of the current. The dynamic characteristics of the electromagnetic dynamic vibration absorber are analyzed analytically and experimentally. The effects of various geometric parameters of the actuator such as the slopes and width/height, and the air gaps on the resulting magnetic force characteristics are evaluated using a finite element model and verified experimentally. A methodology is proposed to achieve magnetic force proportional to current and consistent with the disturbance frequency. The hybrid proportional electromagnetic dynamic vibration absorber is subsequently applied to a single-degree-of-freedom primary system with an acceleration feedback control algorithm for attenuation of primary system vibration in a frequency band around the typical idling vibration frequencies. The effectiveness of the hybrid proportional electromagnetic dynamic vibration absorber is evaluated through simulations and laboratory experiments under harmonic excitations in the 20–30 Hz frequency range. Both the simulation and measurements show that the hybrid proportional electromagnetic dynamic vibration absorber can yield effective attenuation of periodic idling vibration in the frequency range considered.

Dynamic analysis and vibration reduction of articulated silicone gel column with varying geometry

2021 ◽  
pp. 1-13
Author(s):  
Ji-Hou Yang ◽  
Xiao-Dong Yang ◽  
Qing-Kai Han ◽  
Jinguo Liu
Keyword(s):  
Frequency Band ◽  
Vibration Reduction ◽  
Low Frequency ◽  
Vibration Absorber ◽  
Frequency Range ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration ◽  
Silicone Gel ◽  
Resonance Frequencies ◽  
Reduction Effect

Abstract To improve vibration reduction effect in low-frequency band of dynamic vibration absorber (DVA), a novel type of articulated silicone gel column (SGC) is introduced in the design of the tuned dynamic vibration absorber. The nonlinear variation of frequency of SGC with varying geometry is obtained by both finite element simulation and experiments. The most sensitive mode is located, which has wider frequency range by varying the geometry. The polynomial fitting is used to describe nonlinear relation between frequency and geometry. By tuning the geometry, the equivalent stiffness and then resonance frequencies can be manipulated to behave as an active vibration absorber. The vibration reduction experiment of SGC vibration absorbers is investigated. It is found that SGC has better vibration reduction effect in low-frequency band. The experimental results in the current design demonstrate that the vibration reduction effect can reach 94.03% when tuning SCG to the first order main resonance. The dimensions and material parameters of SGC should be altered for specific frequency range and vibration strength.

149 Vibration Suppression of Tilted Vibration System by Dynamic Vibration Absorber with Two Rollers

2004 ◽  
Vol 2004 (0) ◽  
pp. _149-1_-_149-6_
Author(s):  
Yilin SONG ◽  
Hidenori SATO ◽  
Yoshio IWATA ◽  
Toshihiko KOMATSZAKI ◽  
Yoshiyuki KISHIMOTO
Keyword(s):  
Vibration Suppression ◽  
Vibration Absorber ◽  
Vibration System ◽  
Dynamic Vibration Absorber ◽  
Dynamic Vibration

Reduction of vertical abnormal vibration in carbodies of low-floor railway trains by using a dynamic vibration absorber

2017 ◽  
Vol 232 (5) ◽  
pp. 1437-1447 ◽  
Author(s):  
Qunsheng Wang ◽  
Jing Zeng ◽  
Lai Wei ◽  
Cheng Zhou ◽  
Bin Zhu
Keyword(s):  
Simulation Model ◽  
Field Test ◽  
Damping Ratio ◽  
Dynamic Performance ◽  
Vertical Vibration ◽  
Vibration Absorber ◽  
Dynamic Vibration Absorber ◽  
Pitching Motion ◽  
Suspension Parameters ◽  
Dynamic Vibration

A field test on the dynamic performance of a 100% low-floor railway train with five cars was conducted, and a vertical vibration at around 8 Hz was mainly studied for the background of the research. The vibration around 8 Hz, defined as the abnormal vertical vibration, was proved to be due to the pitching motion of the carbodies, which significantly affected the dynamic performance of the vehicle with a maximum increase of 0.309 in the vertical Sperling index. The dynamic vibration absorber theory was applied to reduce the abnormal vibration of carbodies to around 8 Hz by building a vertical mathematic model and a three-dimensional dynamical simulation model. The results of the theoretical analysis show that the stiffness of the articulated device between carbodies is the reason for the pitching motions at around 8 Hz, and the stiffness significantly affects the main frequency of the vertical vibration of carbodies. What’s more, the application of dynamic vibration absorber theory on low-floor railway trains can reduce the vertical abnormal vibration effectively. Yet, reasonable suspension parameters are needed; otherwise, the vibration of carbodies, including the mass ratio, the suspension frequency, the damping ratio, and the suspended location would be aggravated. Optimal suspension parameters of the dynamic vibration absorber system were used in the simulation model, and the result shows a good agreement with the numerical results; the attached dynamic vibration absorber system on carbodies significantly reduces the vibration of carbodies at around 8 Hz. However, it should be noted that the dynamic vibration absorber is only effective at high-speed stage (beyond 40 km/h) where the pitching motion of carbodies is obvious; this conclusion is consistent with the results of the field test.

Single-Degree-of-Freedom Dynamic Vibration Absorber for Unknown System

2018 ◽  
Author(s):  
Zhang Pandeng ◽  
Liu Zhao ◽  
Zhang Tianfei ◽  
Zhu Yutian ◽  
Zheng Changlong ◽  
...  
Keyword(s):  
Degree Of Freedom ◽  
Vibration Absorber ◽  
Evaluation Function ◽  
Vibration System ◽  
Dynamic Vibration Absorber ◽  
Single Degree Of Freedom ◽  
Technology Application ◽  
Single Degree ◽  
Dynamic Vibration ◽  
Unknown System

Vibration causes problems, and the technology of dynamic vibration absorber is always used to control it. So far, the technology is mature, but based on the known of modes, mass, stiffness, damping and other parameters of the vibration system. For an unknown system or complicated system, how to use this technology is what the paper mainly discusses. The dynamic vibration absorber of this paper is a single-degree-of-freedom, and only one direction is to be controlled. The evaluation function is the ratio between the system vibration response after adding dynamic vibration absorber and the original exciting force, which can reflect the effect of dynamic vibration absorber. After separating the unknown system and the dynamic vibration absorber, based on force analysis, we analyze them separately and deduce the calculating formula of the evaluation function. The order of parameters to be determined is mass, stiffness, and damping. Flow chart is presented on how to use the method. The method is validated by a known system of two degree-of-freedom vibration system. The main innovation of this paper is to propose a method of predicting the effect of adding a single-degree-of-freedom dynamic vibration absorber to an unknown system to control a certain direction. This method doesn’t need to consider the system damping factor. This paper extends the scope of technology application of dynamic vibration absorber.

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